David Cassidy to Sony: I Think You Owe Me!From teen idol to ticked-off plaintiff.

David Cassidy has sued Sony Pictures Entertainment and Sony-owned Screen Gems Inc. for fraud and breach of contract, claiming that the makers of The Partridge Family raked in $500 million over the years from royalties, a spinoff deal and merchandise and he never received his contractually owed share.

Sony begs to differ, however.

"It would seem as though your client does not appreciate the difference between merchandising of The Partridge Family series and merchandising using Mr. Cassidy's name, voice or likeness," wrote studio lawyer Gregory Boone in a letter to Cassidy's attorney, Craig Marshall, in response to a scathing interview the erstwhile Keith Partridge gave on CNN.

"Our right to use the name...of Mr. Cassidy in merchandise expired in the 1970s," Boone continued. "However, we continue to have the unfettered right to merchandise The Partridge Family...and Mr. Cassidy does not share in any such receipts."

"It's just ludicrous and unfair and wrong. It's greed," Cassidy said in August of the perceived slight, telling CNN that he only received $5,000 of the proceeds from all those lunch boxes, beach towels, board games, pillow cases and other Partridge Family goodies sold when the show hit it big.

The 61-year-old singer said at the time that he waited this long to raise the issue because he just found a copy of his original contract in a box that hadn't been opened in 30 years.

Per the lawsuit filed today in Los Angeles Superior Court, Cassidy was owed a 15 percent cut of the merchandise because his popularity helped drive sales, as well as 7.5 percent of the net proceeds of all TV royalties and a financial cut in any spinoffs.

In addition to fraud and breach of contract, he's also suing for open book accounting, misappropriation of right of publicity, negligent misrepresentation, civil conspiracy and constructive fraud.

His attorney contends that Sony and fellow defendants never provided Cassidy with any accounting records and "concocted their scheme" to hide the fact that they owed him money.